Learning.Python

An open journal chronicling a physicist’s journey learning Python.

[vhbpython]

Hello world—conditions apply

OK, time for the first programme. This one is a simple print statement that prints something given that a condition is true.

>>> facingEast = True >>> if facingEast: ... print("Hello, world\nHow is it going?") ...

Which gives the output

Hello, world How is it going?

[vhbpython]

Getting started

The time between my first lesson and when I installed Python was considerable, so I forgot how I installed Python in the first place. It was for good, though, because when I tried to

python --version

from Terminal.app on my Mac it showed me a sorry 2.7.10 figure. So I might as well install python again, and this time get it right. The reason I mention this is because the method I eventually used did, according to my understanding, install all of python but there is a slim chance that it did not and that I ended up using some combination of files from both installs. Either way, give it a go yourself.

Install the latest version of python via Homebrew using the following command:

brew install python

That should have you set up and ready to run. I did encounter a problem, however, where the /usr/local/Frameworks directory could not be created. I am not sure if this is a Brew problem or something else but it can be solved by manually creating the directory and assigning permissions:

sudo mkdir /usr/local/Frameworks

sudo chown $(whoami):admin /usr/local/Frameworks

If at any point Brew does install Python but you do not realise it thanks to an error message you can try linking with

brew link python

And if this throws errors try to force an overwrite:

brew link --overwrite python

Do not do this unless you are sure that there are no dependencies that might be overwritten with sorry consequences.

Finally install PIP for package management using

sudo easy_install pip

You can verify your python installation (and PIP) with

python3 --version

pip -V

Keep in mind that using just python instead of python3 may call a legacy version of Python like 2.7.x and not (the current) version 3.x.

[vhbpython]

Hello world

This is a journal about learning Python for computational physics. This is a side project motivated by my ongoing research which required me to learn Python. I will be writing here after I finish every learning session. The latest stable version of Python as of the time of this writing is 3.7.1.

The resource I am using (at least for the time being) besides the official Python documentation is a book called ‘Computational Physics’ by Rubin Landau et al. (Wiley). As I explore Python I will be doing so at times with organisation and at times without. Bear with me either way: in the end this journal should have enough about Python to help any curious reader get started and then some.